Mobile communications devices such as cell phones are becoming more popular due in part to the capabilities being added to such devices. Far from being simple voice communications tools, modern cell phones and related devices such as Personal Digital Assistants (PDAs) have become versatile digital communications and data processing tools. These devices form an important niche in the growing field of personal digital communications.
One factor that is expected to increase the popularity of mobile devices is the development of third generation (3G) technologies. The designation 3G refers to a collection of standards and technologies that can be used in the near future to enhance performance and increase data speed on cell phone networks. In particular, 3G is an International Telecommunication Union (ITU) specification for the third generation of mobile communications technology. A 3G network may utilize packet-switched data transmission services that mirror the Internet model, such as General Packet Radio System (GPRS) and Universal Mobile Telecommunication System (UMTS). A 3G cell phone would, in theory, be compatible with the 3G languages and standards that support access to public networks (e.g., the Internet) at enhanced data speeds.
Future 3G devices may include features that allow communication with other consumer electronics devices. In particular, the mobile devices may include secondary interfaces for communicating with non-telecom networks. For example, a home networking standard known as Universal Plug and Play™ (UPnP) provides a way for disparate processing devices to exchange data. The UPnP standard defines an architecture for peer-to-peer network connectivity utilizing a wide variety of electronic devices. The UPnP standard includes standards for service discovery, and is mainly targeted for proximity or ad hoc networks.
Various contributors publish UPnP device and service descriptions, thus creating a way to easily connect devices and simplifying the implementation of networks. UPnP is designed to work in many environments, including the home, businesses, public spaces, and on devices attached to the Internet. The UPnP standard is an open architecture that leverages Web technologies and is designed to provide ad-hoc networking and distributed computing.
The UPnP model is designed to support zero-configuration networking and automatic discovery for a wide variety of device categories. This allows a device to dynamically join a network, obtain an IP address, convey its capabilities, and learn about the presence and capabilities of other devices. Other Internet protocols such as Dynamic Host Configuration Protocol (DHCP) and Domain Name Service (DNS) may optionally included in a UPnP network, although they are not required. A device can leave a UPnP network smoothly and automatically without leaving any unwanted state behind.
The UPnP architecture includes mechanisms for discovery of devices on the network and mechanisms for describing capabilities of those devices. The UPnP discovery protocol allows a device to advertise its services to control points on the network by utilizing multicast messages. Multicasting refers to a sending a single copy of data to multiple recipients on an Internet Protocol (IP) network. Devices can multicast one or more service announcement messages. Each message describes an embedded device and/or service available from the message's originator. Other devices on the network listen on the multicast address for these service announcement messages. This information can be used to by the devices to utilize UPnP services.
UPnP provides a convenient way for consumers to build a home network. Due to the particularities of the UPnP protocol, a UPnP home network is typically only accessible within the physical boundaries of the home. Limiting the physical boundaries of the UPnP network makes sense for many applications, and tends to simplify the network topology and increase performance. However, at some point, consumers may want to remotely access their home network while away. There are some solutions available but they are not purely UPnP. For example, they may utilize a non-UPnP gateway that will bridge the UPnP to the remote access technology. One drawback of this solution is that it requires changes in UPnP applications that operate on the remote devices in order to work properly.
Security is another concern when allowing external access to a home network. Home networks should be restrictive in accepting any outside connections for security reasons. Standard access protection mechanisms (e.g. password protected logins) are insufficient to guard against ever increasing intrusion threats on the Internet. To solve this problem, a group of technologies known as virtual private networks (VPN) were developed. A VPN is designed to provide secure access to a local network via untrusted, public networks. A VPN can also ensure that data transferred between remote devices and the local network cannot be read by third-parties.
A VPN gateway can provide safe access to a home network for remote users, although currently these devices are not utilized by typical home-network users. A VPN gateway may also provide remote access to UPnP elements of a network. However, running native UPnP protocols via a VPN connected through mobile networks such as GPRS/UMTS may cause technical problems. For example, some mobile devices may not want to constantly engage in the UPnP multicast traffic, yet may still want to remain accessible to other UPnP devices on the UPnP network. Therefore, to effectively allow remote devices to access a home UPnP network without customizing the UPnP applications, adaptations to the UPnP network may be required.